A sliding cover atop a 3-board door in the main companionway? Or something else.
Sounds OK so far except you should omit the maple. It likes to mold beneath the finish in marine environments. Walnut and cherry will work fine.
And you can make a decorative wood patch to cover almost anything. Just make it so it doesn't warp, seal it well and screw it down uniformly into the bedding. In a glass hull, insure you double drill even your screw pilot holes so water doesn't ingress to the core beneath the glass.
Painted qsawn mahogany covering bolt holes:
http://pic20.picturetrail.com/VOL12/...5/57597734.jpg
The same stock in a cover for the horn hole:
http://pic20.picturetrail.com/VOL12/...9/58622485.jpg